Hi,
Your breeder should have told you what to expect with a new yorkie baby. It's quite normal for your yorkie to seem so quiet and gentle the first week or two. She's adjusting to her new environment.
Then, her "puppy" comes out. That doesn't mean that you have a bad natured dog at all. It does mean that your baby requies training, patience and love.
Being out of the home for 7 -8 hrs a day is a LONG time for a puppy. It's plenty of time for a puppy to develop destructive behaviors. It would be nice if someone could see her mid-day for a little while to give her some attention and time out of the pen.
It's difficult at this age to use a "day care" service because she's probably too young. But we're just reaching the summer months. I bet you could get a local High School student very cheaply to stop in several times per day and to help with training.
I'll be getting another puppy in August. I'll have my 3 kids at home for a month before school starts. I'm putting them to work (but I don't have to pay anything because I feed them!
)
Don't freak out. There are solutions to most puppy problems. She probably needs some stuff to chew on and keep her occupied. When I go out, I do leave the tv on. Although my Lucy doesn't pay much attention to it (except when the Dog Whisperer is on), I think the sound is comforting. If your puppy's big enough, you may want to also try a Thundershirt for comfort.
Good luck, things will improve. Tracey